DR BROWN ON THE PRODUCTION OF SILICON FROM PARACYANOGEN. 31 



effervescing when caught on the point of the flame. After twenty minutes of this 

 treatment, fusion and effervescence had ceased, paracyanogen had disappeared, 

 and was replaced by a greenish- white crust, lining the inside of the tube. On 

 examination, it was found that the glass had been deeply corroded, and was en- 

 crusted, not with paracyanogen or carbon, but with a dense saline substance, of 

 a siliceous character, less fusible than glass. 



These appearances and effects are alike unintelligible on the supposition, 

 which has been already shewn to have been unfounded,* that heat resolves para- 

 cyanogen into cyanogen ; and inexplicable by the only other conjecture which can 

 be made in conformity with the present theory of chemistry, viz. that paracyanogen 

 is decomposed by heat into nitrogen and carbon. By the former, even if it were 

 allowable, the powerful action on the substance of the tube is left without expla- 

 nation ; and if the latter view were adopted, it would be equally necessary and 

 impossible to account for the disappearance of the carbon. 



2. A larger quantity was driven, in the same manner, from place to place in a 

 green glass-tube of German manufacture, containing no oxide of lead, and very 

 refractory in the fire. In this instance, there was very little, if any, action on the 

 glass ; and there was procured, instead of a saline crust, a dark-brown infusible 

 substance like charcoal. A part of this product was immersed in concentrated 

 sulphuric acid, which had no reaction on it even in the state of ebullition ; so that 

 it contained no paracyanogen. It was incombustible in the oxidating flame of the 

 blowpipe, having been only deepened in hue and rendered denser by the ignition ; 

 and when heated in a great excess of melted chlorate of potassa, it did not burn 

 and disappear, although it had been previously reduced to a state of very fine 

 division ; and thus it was not carbon. Projected into fused carbonate of potassa, 

 it dissolved with effervescence ; and there remained a white saline product. The 

 only known elementary bodies which possess these qualities are boron and silicon ; 

 and it is not easy to conceive any compound of nitrogen and carbon likely to dis- 

 play such characters. The last mentioned saline product was moistened with sul- 

 phuric acid, and it was found that alcohol, kindled over the mixture, burned with 

 a flame of the ordinary hue. The mixture, therefore, contained no boracic acid, 

 and, consequently, the matter projected into the carbonate was not boron. It sunk 

 in sulphuric acid of the density of 1.8. In short, it corresponded in every dis- 

 tinctive property with silicon. 



3. A little crucible, of Berlin porcelain, was filled with paracyanogen ; and, 

 after the lid had been tightly luted on, it was imbedded in stucco paste within a 

 larger crucible. The gypsum having set and dried, the apparatus was kept at a 

 white heat for an hour and a half. The residue of this process resembled the last, 



* Op. cit. sect. iii. p. 168, et seq. 



